A side of sweetness
April 17, 2007
by Jeff Gelski
Prebiotics have found their way into various food and beverage formulations thanks to their health benefits, especially in the area of digestion. Some prebiotics offer additional pluses in sweetness, which should not be surprising since prebiotics may contain fructose or sucrose.
One prebiotic, inulin, is a chain of fructose units ranging from 2 to 60 units in each link, said Scott Turowski, technical sales representative for Sensus America, L.L.C., Monmouth Junction, N.J. Inulin with shorter chain lengths, such as 10 or under, is a partially hydrolyzed product that works like sugar or corn syrup, Mr. Turowski said.
"It works like a sweetener," he said. "It has more than 75% solubility and has humectant properties that sugars may have."
While this form of inulin from Sensus may offer a sweetness level nearly half that of sucrose, other inulin products may be about 10% as sweet, he said. The sweeter inulin may work in various applications, like bars and yogurts. It may not work in chocolate, which would need more of a crystalline product, he said.
Inulins of various chain lengths were the focus of a recent study involving researchers from the Louisiana State University Agricultural Center in Baton Rouge, La., and Victoria University, Melbourne, Australia. They examined fat-free plain yogurt manufactured with inulins of various chain lengths. Results appeared in the April issue of the Journal of Food Science (Volume 72, Issue 3).
The study was initiated to determine the effect of short-chain, medium-chain and long-chain inulins on the physiochemical, sensory and microbiological characteristics of fat-free plain yogurt containing the probiotic Lactobacillus acidophilus. The short-chain inulin had a significantly lower pH and higher flavor scores than the long-chain inulin. The long-chain inulin had better body and texture than the remaining yogurts. Yogurts containing prebiotics of different chain lengths had comparable L. acidophilus counts. Inulins of various chain lengths did not affect viscoscity, color and product appearance.
Sensus, Orafti Active Food Ingredients, Malvern, Pa., and Cargill, Minneapolis, all supply inulin ingredients. Mr. Turowski said Sensus will change the name of its Frutalose L90 inulin product to Frutalose L92 since fiber content in the ingredient has improved to 92% from 90%. Orafti Active Food Ingredients offers Beneo inulin, a mixture of oligosaccharides and polysaccharides. The sweetness of Beneo inulin products may range between 10% and 35% as sweet as sucrose.
Cargill offers Oliggo-Fiber inulin, a soluble dietary fiber. The company had raspberry flavor Oliggo-Fiber inulin sticks at its booth during the Natural Products Expo West show in March in Anaheim, Calif. Cargill said the sticks may be added to beverages to provide flavor.
Another prebiotic, Litesse polydextrose, is a polysaccharide composed of randomly cross-linked glucose units, according to Danisco. The company said Litesse polydextrose is not sweet.
"However, it is compatible with sugars and high-potency sweeteners, allowing the sweetness of formulations to be easily balanced," Danisco said.
Tate & Lyle, P.L.C., London, plans to launch a soluble corn fiber that is prebiotic later this year, said Doris Dougherty, a senior food scientist with Tate & Lyle and based in Decatur, Ill. Although it’s not sweet, the soluble corn fiber may affect browning like sugar does.
"The soluble corn fiber is very corn syrup-like in terms of functionality," she said.
More advancement in the sweetness content of prebiotics may be on the way, according to an article published by the foodnavigator.com web site last December. It said scientists from Denmark and South Korea have shown the synthesis of prebiotic oligosaccharides could have a relative sweetness of 80% of sucrose. Results of the research were published in the journal Enzyme and Microbial Technology.
Digestion effects remain the main benefit of prebiotics as they assist healthy bacteria known as probiotics.
A joint group of the Food and Agriculture Organization of the United Nations/World Health Organization defined prebiotics as "non-digestible food ingredients that beneficially affect the host by selectively stimulating the growth of one or a limited number of bacterial species in the colon, such as Bifidobacteria and Lactobacilli, which have the potential to improve host health." The group defined probiotics as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host."
Food formulators and scientists still have much to learn about prebiotics, Ms. Dougherty said.
"We are investing in a nutritional research effort," Ms. Dougherty said of Tate & Lyle. "We are spending a great deal of time and money to understand (prebiotics) better and to understand how our products perform specifically."